Casting form



Nov. 27, 1956 E. M. SWENSON 2,771,656

CASTING FORM Filed Nov. 23, 1953' 2 Sheets-Sheet l IN V EN TOR. .fl/yene MSWe/Iwn By 12 0C K/M Nov. 27, 1956 E. M. SWENSON CASTING FORM Filed Nov. 25, '1953 2 Sheets-Sheet 2 IN V EN TOR. fay me M Sire/7500 Af/amey United States Patent O CASTING FORM Eugene M. Swanson, Hazelcrest, Ill., assignor to Calumet Flexicore Corporation, East Chicago, Ind., a corporation of Indiana Application November 23, 1953, Serial No. 393,569

4 Claims. (Cl. 25121) This invention relates to a casting form for the manufacture of concrete beams, and more particularly of socalled stadium beams. Beams having the cross section of an L are widely used in constructing stadia and amphitheatres where ascending rows of seats are required. These beams have one arm of the L rather short and thick, while the other arm of the L is comparatively long and thin. It is possible to arrange these beams so that one part of one L overlaps another part of the L of a different beam and thus provide a series of steps. Beams of this character are generally prestressed and may be made in lengths up to or feet.

Considerable ditficulty has been experienced in casting such beams in quantity. Due to the shape of the beam section, difi'iculty has been experienced in designing forms which can expeditiously handle the casting. Removal of the casting from the form has made it necessary to design the form so that the various sides may be dismantled. This has required assembling the form in preparation for casting a new beam and has thus involved substantial labor and time. In addition, the lines of cleavage or separation between the form parts has been responsible for ridges or fins appearing on the finished beam. Since it is desired to use the beam without any further operations or without any further covering, the presence of such fins or ridges has made it necessary to remove such fins or ridges and smooth the concrete.

This invention provides a form having a minimum number of parts to be dismantled and having the desired characteristic of being readily freed from the finished beam. A form embodying the present invention may be readily filled with concrete mix and may be constructed out of conventional sheet material and angle iron or strip steel. In order that the invention may be understood, an exemplary embodiment thereof will now be described in connection with the drawings, it being understood, however, that substantial variations may be made without departing from the spirit of the invention except as defined by the appended claims.

Referring, therefore, to the drawings:

Figure l is a perspective view of a form embodying the present invention, the form being in condition for receiving a concrete mix and the drawing showing an intermediate part of the form removed.

Figure 2 is a transverse section of the form illustrated in Figure 1.

Figure 3 is an enlarged detail of the form near the bottom thereof.

The casting form illustrated is constructed to handle two beams. As will be more fully appreciated after the construction has been explained, the simultaneous casting of two beams makes for a balanced form construction. However, each casting unit for handling one beam may be isolated from the others so that a casting form may be constructed to handle one stadium beam at a time or additional units may be added for handling more than two beams.

Each casting unit comprises straight sheet steel wall 10 r6 CC extending downwardly from free edge 11 to corner 12. For convenience, the normal position of the casting form will be assumed as illustrated in the drawings so that side 10 will normally be vertical. The sheet steel extends horizontally from corner 12 to make bottom 14. The sheet steel comprising the form continues from bottom 14 to corner 15 and then rises vertically to make side 16.

It is understood that at least corner 15 is rounded so that the sheet steel will not crystallize but will retain its flexibility. Side 16 of the form extends upwardly to corner 17 and then continues horizontally at 18 to corner 19 and then vertically to make side 20 having free edge 21.

The entire form extending from free edge 11 along the metal to free edge 21 is continuous and smooth. It may be necessary to butt weld several sheets of steel to make the complete form. In such case, it is desirable to grind the weld joints so that the inside surface of the metal will be smooth, thus imparting a smooth face to the concrete.

The length of the form, this being the dimension perpendicular to the plane of the paper in Figure 2, may be as great as desired and may necessitate welding the sheet steel at various points along the length of the form. The same precautions with regard to smoothing the form surface at the casting side should be observed.

The dimensions of the various parts of the form will be designed to suit a desired stadium beam. Thus the overall length of the stadium beam, this being the distance between free edge 11 and bottom form, may be about 33 inches. The maximum width which may be considered as the distance between free edge 11 and free edge 21 may be around 11 inches, while the width or thickness of the lower part of the beam as determined by the distance between sides 10 and 16 of the casting form may range from about 3 /2 inches at the bottom to about 4 inches at the top, this being respectively near bottom 14 and adjacent corner 17.

As will be more fully explained later, the construction of the formpermits springing sides 16 and 20 on the one hand from side 10 on the other hand so that sides 16 and 10 of the form are not necessarily parallel during the casting operation. In many conventional forms it has been necessary to have side 16 diverge away from side 10 as the top of the form was approached to impart the necessary draw taper to the beam. This would permit the finished beam to be pulled out of the form. However, in the construction illustrated, the flexibility of the form is such that sides 16 and 10 may be parallel or may even approach each other in the direction of the open top of the form.

A companion form unit whose parts carry similar primed numbers is provided. The two form units are disposed so that opposed sides 10 and 10 are parallelQ portions of thereof being upwardly directed and facing channel 25.

The web of channel 27 is substantially flush with the outer surfaces of bottoms 14 and 14 of the companion units. Reinforcing plate 29 is disposed below bottoms 14 and 14' and the web of channel 27. Plate 29 is of heavy steel and is just wide enough to reach to corners 15 and 15' respectively. Plate 29 may be attached to bottoms 14 and 14' and to channel 27 in any desiredmanner, such as by spot welding. It is also possible to bolt the parts together.

14 of the casting A number of these rods indicated by 53 are shown,

At spaced intervals along the length of the form, a reinforcing skeleton framework, generally indicated by 31, is provided. Framework 31 consists of outer vertical member 32 extending the full depth of the form. Welded or otherwise attached to member 32 are horizontal members 33 and 34. Horizontal member 33 extends beneath horizontal portion 18 of a casting unit, while horizontal member 34 extends along the bottom of the unit with bottom edge 35 of member 34 being substantially in line with the outer face of bottom 14 of the casting form unit. Vertical reinforcing member 37 extends between the inner ends of horizontal members 33 and 34. As will be observed in Figure 1, vertical member 37 may consist of an angle iron, one flange of which is flush against the outer surface of wall 16 of the casting form unit. Horizontal member 33 may, if desired, consist of an angle iron. The same is true of vertical member 32 or that part of member 32 disposed against part 19 of the casting form unit.

A similar reinforcing framework 31' is provided for the companion casting unit. Reinforcing frames 31 and 31' are conveniently disposed as pairs opposite each other along the length of the form. The spacing between adjacent reinforcing frameworks will vary depending upon the gauge of metal used in the form, the thickness of the beam, the prestressing load present on the form, and other factors.

Disposed along the outside of form portion 19 near free edge 21 is angle iron 40 having one flange disposed against the end portion of the form side and having the other flange generally flush with the web of flange 25. Flange 40 is similarly provided for the companion unit. In practice, angle iron 40 will extend the full length of the form. Vertical reinforcing members 32 will extend up to the inside face of the flange of angle iron 40. The same is true of angle iron 40.

At spaced intervals along the top of the casting mold means are provided for accommodating mold-retaining angle irons 42. These may be disposed at the regions where reinforcing frames 31 and 31' occur. The horizontal flanges of angle irons 40 and 40 are provided with suitable apertures through which bolts 43 and 43' may extend. These bolts pass through apertures in the flange of angle iron 42 and are retained in position by suitable nuts. It is understood that angle irons 42 are readily removable, these angle irons being retained in position during filling and casting and being removed when the cast beam is to be discharged. Instead of angle irons 42, flat strips of steel may be used.

The casting form requires bulkheads at the two ends. Referring to Figure l, bulkheads 45 and 46 are illustrated. Since the two bulkheads are similar, the same reference numerals will be used. The bulkheads have a T shape and are retained in position upon the form by bolts 48 to 51 inclusive. Bolts 48 and 49 are carried by vertical reinforcing members 37 and 37' at the ends of the form. Bolts 50 and 51 are carried by that part of vertical reinforcing member 32 and 32' that is adjacent side 19 of the casting form. It is understood, of course, that only those reinforcing members which occur at the very ends of the form are provided with these bolts. The bulkhead has registering apertures therethrough for accommodating the bolts, after which nuts are disposed to maintain the bulkhead in position.

The bulkheads also have means for gripping the ends ofprestressing wires or rods embedded in the concilrlete. t ese rods generally consisting of cold drawn low carbon steel. The ends of prestressing rods 53 pass through apertures provided in the bulkheads. Suitable means for gripping the ends of the wires or rods may be provided. Thus the ends of the wires may be threaded and sleeves 54 having enlargedrheads may be provided. By turningthe sleeve nuts, the various rods may be tensioned to a suitable value as determined by the specifications for the beam. In some instances a steel mesh or screen, generally indi- 4 cated by 56, may be disposed within each form, the mesh being welded to some or all of the prestressing rods and providing reinforcement.

Assuming that the form is in the condition illustrated in Figure 1, it may be disposed upon the ground or a suitabie flat support and filled with a concrete mix. During the filling, the entire casting mold is preferably vibrated to tamp the concrete firmly into the mold. Thus air bubbles are eliminated and the mold is filled with a dense mass of plastic concrete. After the mold has been.

filled, it may be disposed in a steam chamber overnight for curing, or the concrete may be allowed to set under any desired conditions. After the concrete has set, cross beams or angle irons 42 are removed and the bulkheads are unbolted from the casting form and may be disconnected from the prestressing rods. It bolts 48 to 51 are removed, the bulkheads will come outwith the cast beams.

When the bulkheads are removed and cross reinforcing members 42 are removed, sides 16 and 16 of the forms are sprung outwardly. Due to the fact that rounded corners 15 and 15 are unsupported, the casting forms will yield at these corners and open a limited amount. One or more jacks may be disposed between pairs of bolts 43 and 43' instead of the angle irons, and these jacks can be used to spread the form. It is also possible to provide the necessary mold-opening action by pulling on members 32 and 32'.

It will be noted that the reinforcing frameworks 31 and 31' can be movedslightly with respect to rounded corners 1S and 15' assuming that the form is seated on a level support. In many instances, the removal of cross beams 42 will suffice so that the form units will open underthe weight of the finished concrete. It is clear from Figure 2 that the concrete beam is top heavy and that therewill be a tendency for the beam to exert an opening force around the mold sides. It is also-possible to turn the entire mold upside down and the weight of the cast beams will be enough to spring the mold.

In the event that the bulkheads are still bolted or attached to the prestressing rods when the cast beams come out, it will be necessary to separate the bulkheads thereafter.- This may be done either by unscrewing the sleeve nuts if those are used, or by sawing the ends of the prestressing rods if an expendable retainer for the wire or rod ends is used.

While the casting form may be constructed in any number of units, the double unit illustrated here is convenient and has desirable operating advantages.

The two units making a form may have their inside faces 10 and 10 flush with no spacers therebetween. However, the irons between the inside faces make the units more rigid. If desired, vertical irons between angle irons 25' and 27 may be provided for reinforcing the inside faces of'each unit. The forms may be constructed of heavy steel. If desired, the two units may be separated. If separated, it may be desirable to anchor side 10 and move the opposing side only.

What is claimed is:

1. A form for casting a pair of L-shaped beams, said form'comprising a pair of sheet steel casting units, each casting unit having an open top with a straight inside wall extending downwardly to the unit bottom, the sheet steel continuing to make a first rounded corner and continuing horizontally to make the bottom and then being shaped to make a second rounded corner and extending upwardly to form a second side, the steel of said second side being shaped to provide an offset near the top of said form, said offset extending away from the first side and the steel continuing straight up to the open top of the form, means for securing said two casting units so that the straight inner side portions are disp osed in opposed parallel relation, a. reinforcing plate extending along the bottom of both units up to but short of the second rounded corner of each unit, means for maintaining the top free edges of the insidewalls in fixed prede termined relation, removable means across the top of said form for bolting the outer sides in predetermined relation, bulkheads for the form ends, the outer sides of the two form units being springable outwardly on their respective second corners to release the cast beam, and reinforcing means at the outer sides of each form unit, said reinforcing means extending downwardly for limiting the springing of the forms.

2. The construction according to claim 1 wherein reinforcing frameworks are provided spaced at intervals lengthwise of the form on each side thereof, said frameworks extending laterally from the outer sides of the casting units, said frameworks extending downwardly to points which are above the reinforcing plate along the bottom of the units in the normal position of the casting form so that the reinforcing frames may move before striking a supporting surface upon which the reinforcing plate itself may be resting when opening the form.

3. A form for casting a pair of L-shaped beams, said form comprising a pair of sheet steel casting units, each casting unit having an open top with a straight inside wall extending downwardly to the unit bottom, the steel continuing to make a first rounded corner and continuing horizontally to make the bottom and then continuing to make a second rounded corner and extending upwardly to make the outer side of the form, said outer side having an outwardly extending ofl'set near the top of the form with the steel continuing after the offset straight up to the top, the steel at the top then being bent outwardly to form a horizontal flange, a supporting plate secured to the flat bottoms of both of said casting units, said supporting plate stopping short of the second rounded corner for each unit, a channel having the web disposed on said bottom plate and between the opposed inside walls of the two casting units, said channel having the flanges reinforcing the straight sides against flexing at the first rounded corner for both units, a channel disposed at the top free edges of the inside walls, said two channels having their flanges extending toward each other and being rigidly attached to the casting form walls, the web of said second channel being substantially flush with the flanges at the outer walls of the casting units, bulkheads for the ends of said casting units, reinforcing means for the overhanging parts of the two casting units formed by the horizontal offsets of the outer walls, said reinforcing means extending down to substantially flush with the bottom portions of the casting forms and detachable means resting on the flanges of the outer casting unit sides and on the web of the second channel for locking said casting forms to prevent the outer sides of the forms from springing outwardly, said outer sides being. adapted to spring outwardly when unlocked with the reinforcing means limiting the amount of spring.

4. The construction according to claim 3 wherein said reinforcing means include restangular frames at spaced intervals along the length of the forms, said rectangular frames extending beneath the overhanging portions of the outer walls of the casting units.

References Cited in the file of this patent UNITED STATES PATENTS 1,025,508 Caldwell May 7, 1912 1,054,577 Logan Feb. 25, 1913 1,436,385 Darling Nov. 21, 1922 1,925,733 Pandolfe Sept. 5, 1933 2,306,107 Henderson Dec. 22, 1942 2,596,052 Stockmar May 6, 1952 2,614,309 Price Oct. 21, 1952 FOREIGN PATENTS 215,863 Great Britain May 22 1924 

